U.S. patent application number 17/336592 was filed with the patent office on 2021-12-09 for thermal fixing apparatus and image forming apparatus.
The applicant listed for this patent is CANON KABUSHIKI KAISHA. Invention is credited to Hirotaka Fukushima, Yasushi Hoshi, Yoshiko Igarashi, Hidetaka Nanao, Yusuke Owaki.
Application Number | 20210382426 17/336592 |
Document ID | / |
Family ID | 1000005638240 |
Filed Date | 2021-12-09 |
United States Patent
Application |
20210382426 |
Kind Code |
A1 |
Fukushima; Hirotaka ; et
al. |
December 9, 2021 |
THERMAL FIXING APPARATUS AND IMAGE FORMING APPARATUS
Abstract
A thermal fixing apparatus, including a rotatable first member;
a heater heating the first member; a rotatable second member
forming a nip portion with the first member; and a pressurizing
member disposed inside the first member, and having a contact
surface with an inner surface of the first member. The pressurizing
member includes a surface layer constituting the contact surface,
and the surface layer comprises a diamond-like carbon film
containing a hydrogen atom (H), a carbon atom (C) and a silicon
atom (Si). 100.times.(H)/((H)+(C)) is 5 or less.
100.times.(Si)/((Si)+(C)) is 1 to 20. Between the contact surface
and an inner circumferential surface of the first member, an oil
film containing a fluorinated oil and a silicone oil is
present.
Inventors: |
Fukushima; Hirotaka;
(Tochigi, JP) ; Owaki; Yusuke; (Tochigi, JP)
; Igarashi; Yoshiko; (Tochigi, JP) ; Nanao;
Hidetaka; (Iwate, JP) ; Hoshi; Yasushi;
(Iwate, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
CANON KABUSHIKI KAISHA |
Tokyo |
|
JP |
|
|
Family ID: |
1000005638240 |
Appl. No.: |
17/336592 |
Filed: |
June 2, 2021 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G03G 15/2057 20130101;
G03G 2215/2035 20130101; G03G 15/206 20130101; G03G 2215/2038
20130101; G03G 15/2064 20130101 |
International
Class: |
G03G 15/20 20060101
G03G015/20 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 9, 2020 |
JP |
2020-100377 |
Claims
1. A thermal fixing apparatus, comprising: a first member which is
rotatable; a heater which heats the first member; a second member
which is rotatable, and forms a nip portion with the first member
such that a recording material can be sandwiched therebetween; and
a pressurizing member which is disposed inside the first member,
has a contact surface with an inner surface of the first member,
and presses the first member against the second member, wherein the
pressurizing member includes a surface layer constituting the
contact surface, the surface layer comprises a diamond-like carbon
film, the diamond-like carbon film contains a hydrogen atom, a
carbon atom, and a silicon atom, the proportion of the number of
the hydrogen atom (H) to the sum of the number of the hydrogen atom
(H) and the number of the carbon atom (C) (100.times.(H)/((H)+(C)))
in the diamond-like carbon film is 5 or less, the proportion of the
number of the silicon atom (Si) to the sum of the number of the
carbon atom (C) and the number of the silicon atom (Si)
(100.times.(Si)/((Si)+(C))) in the diamond-like carbon film is 1 or
more and 20 or less, and wherein an oil film is present between the
contact surface and an inner circumferential surface of the first
member, the oil film containing a fluorinated oil and a silicone
oil.
2. The thermal fixing apparatus according to claim 1, wherein the
silicon atom is contained in the diamond-like carbon film in a
state where the silicon atom is bonded to the carbon atom.
3. The thermal fixing apparatus according to claim 1, wherein the
first member is a fixing belt having a sleeve shape.
4. The thermal fixing apparatus according to claim 3, wherein the
fixing belt includes a base having a sleeve shape, and a polyimide
film which is located on the side of the inner circumferential
surface of the base and constitutes the inner surface to be brought
into contact with the surface layer of the pressurizing member.
5. The thermal fixing apparatus according to claim 1, wherein the
pressurizing member includes the heater, and the heater comprises
heater base, a resistance heating element, and the diamond-like
carbon film.
6. The thermal fixing apparatus according to claim 5, wherein the
heater base contains at least one selected from the group
consisting of aluminum nitride, aluminum oxide, and silicon
nitride.
7. An image forming apparatus, comprising: a thermal fixing
apparatus which heats an unfixed toner image on a recording
material to fix the unfixed toner image onto the recording
material, the thermal fixing apparatus including: a first member
which is rotatable; a heater which heats the first member; a second
member which is rotatable, and forms a nip portion with the first
member such that a recording material can be sandwiched
therebetween; and a pressurizing member which is disposed inside
the first member, has a contact surface with an inner surface of
the first member, and presses the first member against the second
member, wherein the pressurizing member includes a surface layer
constituting the contact surface, the surface layer comprises a
diamond-like carbon film, the diamond-like carbon film contains a
hydrogen atom, a carbon atom, and a silicon atom, the proportion of
the number of the hydrogen atom (H) to the sum of the number of the
hydrogen atom (H) and the number of the carbon atom (C)
(100.times.(H)/((H)+(C))) in the diamond-like carbon film is 5 or
less, the proportion of the number of the silicon atom (Si) to the
sum of the number of the carbon atom (C) and the number of the
silicon atom (Si) (100.times.(Si)/((Si)+(C))) in the diamond-like
carbon film is 1 or more and 20 or less, and wherein an oil film is
present between the contact surface and an inner circumferential
surface of the first member, the oil film containing a fluorinated
oil and a silicone oil.
Description
BACKGROUND
[0001] The present disclosure relates to a thermal fixing apparatus
and an image forming apparatus including thermal fixing
apparatus.
DESCRIPTION OF THE RELATED ART
[0002] Diamond-like carbon (hereinafter, also referred to as "DLC")
is used as a surface coating material for a sliding member because
of its high friction wear properties. To stabilize the sliding
properties, a lubricant is applied to its sliding surface.
[0003] Japanese Patent Application Laid-Open No. 2015-34980
discloses a fixing apparatus including a rotatable first member
heated by a heat source, a rotatable second member which forms a
nip portion with the first member such that a recording material
can be sandwiched therebetween, and a pressurizing member which is
disposed inside the first member, has a contact surface with
respect to an inner surface of the first member, and presses the
first member against the second member, in which a surface layer
forming the contact surface of the pressurizing member with respect
to the inner surface of the first member is a specific diamond-like
carbon film. This patent literature also discloses application of a
greasy heat-resistant lubricant containing fluorine-based fine
particles and a fluorine-based oil between the inner surface of the
first member (fixing belt) and the surface layer.
[0004] However, there is a demand for a further enhancement in
durability of thermal fixing apparatus included in
electrophotographic image forming apparatuses.
SUMMARY
[0005] At least one aspect of the present disclosure is directed to
providing a fixing apparatus having further enhanced durability.
Another aspect of the present disclosure is directed to providing
an electrophotographic image forming apparatus which can stably
form high-quality electrophotographic images.
[0006] According to at least one aspect of the present disclosure,
there is provided a thermal fixing apparatus, comprising: a first
member which is rotatable; a heater which heats the first member; a
second member which is rotatable, and forms a nip portion with the
first member such that a recording material can be sandwiched
therebetween; and a pressurizing member which is disposed inside
the first member, has a contact surface with an inner surface of
the first member, and presses the first member against the second
member, wherein the pressurizing member includes a surface layer
constituting the contact surface, the surface layer comprises a
diamond-like carbon film, the diamond-like carbon film contains a
hydrogen atom, a carbon atom, and a silicon atom, the proportion of
the number of the hydrogen atom (H) to the sum of the number of the
hydrogen atom (H) and the number of the carbon atom (C)
(100.times.(H)/((H)+(C))) in the diamond-like carbon film is 5 or
less, the proportion of the number of the silicon atom (Si) to the
sum of the number of the carbon atom (C) and the number of the
silicon atom (Si) (100.times.(Si)/((Si)+(C))) in the diamond-like
carbon film is 1 or more and 20 or less, and wherein an oil film
containing a fluorinated oil and a silicone oil is present between
the contact surface and an inner circumferential surface of the
first member. According to further aspect of the present
disclosure, there is provided an image forming apparatus including
a thermal fixing apparatus which heats a toner image on a recording
material to fix the toner image onto the recording material,
wherein the thermal fixing apparatus is the thermal fixing
apparatus described above.
[0007] Further features of the present disclosure will become
apparent from the following description of exemplary embodiments
with reference to the attached drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 is a schematic cross-sectional view illustrating one
example of a thermal fixing apparatus according to one aspect
according to the present disclosure.
[0009] FIG. 2 is a cross-sectional view of a heater included in
thermal fixing apparatus according to one aspect according to the
present disclosure.
[0010] FIG. 3 is a cross-sectional view of an image forming
apparatus according to one aspect according to the present
disclosure.
[0011] FIG. 4 is a diagram illustrating a film forming apparatus
which forms a DLC film used in the thermal fixing apparatus
according to one aspect according to the present disclosure.
[0012] FIG. 5 shows the results of measurement of the coefficient
of friction obtained from a pin plate test performed on the DLC
according to the present disclosure.
[0013] FIG. 6 is a spectrum of the 2p orbital of Si in the DLC film
where the spectrum is obtained by XPS analysis.
DESCRIPTION OF THE EMBODIMENTS
[0014] Preferred embodiments of the present disclosure will now be
described in detail in accordance with the accompanying
drawings.
[0015] A preferred embodiment according to the present disclosure
will now be specifically described with reference to the drawings.
It should be noted that the present disclosure is not limited only
to the following embodiment, and a variety of modifications can be
made and implemented without departing from the scope of technical
ideas of the present disclosure.
[0016] The thermal fixing apparatus according to one aspect of the
present disclosure includes a rotatable first member, a heater
which heats the first member, a rotatable second member which forms
a nip portion with the first member such that a recording material
can be sandwiched therebetween, and a pressurizing member which is
disposed inside of the first member, has a contact surface with an
inner surface of the first member, and presses the first member
against the second member.
[0017] The pressurizing member includes a surface layer forming the
contact surface with the inner surface of the first member. The
surface layer includes a diamond-like carbon film.
[0018] The diamond-like carbon film contains a hydrogen atom, a
carbon atom, and a silicon atom. The proportion of the number of
the hydrogen atom (H) to the sum of the number of the hydrogen atom
(H) and the number of the carbon atom (C) (100.times.(H)/((H)+(C)))
in the diamond-like carbon film is 5 or less. The proportion of the
number of the silicon atom (Si) to the sum of the number of the
carbon atom (C) and the number of the silicon atom (Si)
(100.times.(Si)/((Si)+(C))) in the diamond-like carbon film is 1 or
more and 20 or less. Furthermore, an oil film containing a
fluorinated oil and a silicone oil is present between the contact
surface and the inner circumferential surface of the first
member.
[0019] It is considered that the DLC film containing silicon
(hereinafter, also referred to as "Si-DLC") has a silanol group on
its surface because the DLC film contains silicon. It is considered
that the presence of the silanol group increases the affinity with
the oil film containing a silicone oil.
[0020] It is also considered that higher lubrication is
demonstrated by the presence of an oil film containing both the
silicone oil and the fluorinated oil on the surface of the Si-DLC
film.
[0021] FIG. 5 shows the results of measurement of the coefficient
of friction of the Si-DLC film according to the present disclosure
by a pin plate test using a friction wear tester (trade name:
FPR2100, available from RHESCA Co., LTD.). It shows a result of the
case where a lubricant containing a fluorinated grease and a
silicone oil is used and a result of the case where only the
fluorinated grease is used.
[0022] The Si-DLC film is placed on a surface of a ceramic plate.
Using a pin with a distal end made of polyimide (trade name:
VESPEL, available from E. I. du Pont de Nemours and Company) having
a diameter of 5 mm, the pin and the DLC film were slid by the plate
reciprocally moved at 32 mm/sec under a load of 100 g at an
environmental temperature of 200.degree. C. The results show that a
lubricant containing the fluorinated grease and the silicone oil
has a lower coefficient of friction.
[0023] Although the mechanism of action by which use of the
lubricant containing the silicone oil and the fluorinated oil
(fluorinated grease) results in such an effect of improving
lubrication is not clarified, it is considered that since the
silicone oil and the fluorinated oil have less affinity each other,
the oils are mutual lubricate each other, and therefore, the
sliding resistance may be reduced.
[0024] Use of the sliding member according to the present
disclosure as the pressurizing member in the fixing apparatus can
prolong the life of the fixing apparatus. In other words, according
to the present disclosure, the durability life of the image forming
apparatus can be increased by use of a thermal fixing apparatus
having a durability life prolonged by a pressurizing member having
lubrication enhanced by the Si-DLC film, the fluorinated oil, and
the silicone oil.
[0025] FIG. 1 is a schematic cross-sectional view of one example of
a pressurizing member according to the present disclosure and a
thermal fixing apparatus including the pressurizing member. The
thermal fixing apparatus illustrated in FIG. 1 includes a first
member, a second member, and a pressurizing member which presses
the first member and slides with the first member.
[0026] A fixing belt 120 as the first member has a sleeve shape and
is rotatable. The sleeve shape indicates a shape of an endless
band. A pressurizing roller 130 as the second member forms a nip
portion with the fixing belt 120 such that a recording material 141
can be sandwiched therebetween, and is rotatable. A heater 200,
which also serves as the pressurizing member, is disposed on an
inner circumferential surface of the fixing belt 120 at the nip
portion. The heater 200 is brought into contact with the inner
circumferential surface of the fixing belt 120 to press the fixing
belt. As a result of rotation of the fixing belt 120, a sliding
surface is formed by the inner circumferential surface of the
fixing belt 120 and the surface of the heater base 211.
[0027] The fixing belt 120 includes a stainless steel base having a
sleeve shape, a silicone rubber layer disposed on the outer
circumferential surface of the base, and a perfluoroalkoxyalkane
resin-containing layer (PFA layer) disposed on the silicone rubber
layer. The fixing belt 120 may include a resin film which forms the
inner circumferential surface. The resin film which forms the inner
circumferential surface preferably contains polyimide. The fixing
belt 120 can have any size without any particular limitation. For
example, the diameter is about 30 mm. In the fixing belt 120 having
a diameter of about 30 mm, the stainless steel base, the silicone
rubber layer, the PFA layer, and the polyimide film have
thicknesses of, for example, about 600 .mu.m, about 300 .mu.m,
about 20 .mu.m, and about 1 to 20 .mu.m, respectively.
[0028] Pressurizing roller 130 includes a stainless steel core 131,
a silicone layer 132 disposed on the outer circumferential surface
thereof, and a PFA layer 133. The pressurizing roller 130 can have
any size. For example, the diameter is about 30 mm. In the
pressurizing roller 130 having a diameter of about 30 mm, the
silicone layer 132 and the PFA layer 133 have thicknesses of, for
example, about 3 mm and about 40 .mu.m, respectively.
[0029] FIG. 2 illustrates a schematic cross-sectional view of one
example of the heater 200. The heater 200 includes a heater base
211, a resistance heating element 212, and a thermistor (not
illustrated) as a temperature sensor. The heater base 211 has a
shape of a flat platy stripe having a size of about 400 mm.times.8
mm where the longitudinal direction thereof is defined as the
direction intersecting perpendicular to the conveying direction
(the arrow direction in FIG. 1) of the recording material 141.
Although any material can be used as a material for the heater base
211, the material should be an insulating material because the
resistance heating element 212 is formed. The material is
preferably aluminum nitride. The material for the heater base 211
may have high thermal conductivity so that heat from resistance
heating element 212 is readily conducted to the fixing belt 120.
For this reason, aluminum oxide or silicon nitride can be used
besides aluminum nitride. The resistance heating element 212 is
subjected to insulating coating with a glass layer 213.
[0030] The surface of the heater base 211 sliding with the inner
circumferential surface of the fixing belt includes a coating of an
Si-DLC film 214 having a thickness of 0.5 .mu.m. In the number of
hydrogen atoms (H), the number of silicon atoms (Si), and the
number of carbon atoms (C) in the Si-DLC film, the value of the
expression (100.times.(H)/((H)+(C))) is 5 or less and the value of
the expression (100.times.(Si)/((Si)+(C))) is 1 or more and 20 or
less. A lubricant oil containing a fluorinated oil and a silicone
oil is applied onto the sliding surface.
[0031] It is known that hydrogen contained in the DLC film reduces
the hardness thereof. For this reason, preferred is a substantially
hydrogen-free DLC film excluding inevitable components in
production or a gas adsorbed on the surface of the film.
Specifically, the hydrogen content is desirably equal to or less
than the error of measurement in analysis by an analyzer such as
elastic recoil detection analysis (or ERDA) using ion beams. For
this reason, in the DLC, the proportion of the number of hydrogen
atoms (H) to the number of carbon atoms (C) expressed by the
expression (100.times.(H)/((H)+(C))) is preferably 5 or less.
[0032] An intermediate layer for enhancing adhesion may be disposed
between the heater base 211 and the Si-DLC film 214. The
intermediate layer can be formed of Ti, Cr, Si, or C, or a mixture
or compound thereof by a method such as physical vapor deposition
or chemical vapor deposition.
[0033] As illustrated in FIG. 1, the heater 200 is supported by a
heater holder 111 having a semi-arc tub-like cross-section and a
reinforcing plate 112 having an inverted U-shaped cross-section. In
other words, the heater holder 111 to which the heater 200 is fixed
is provided with the reinforcing plate 112. The heater holder 111
is made of a liquid crystal polymer resin having high heat
resistance. Hereinafter, the heater 200, the heater holder 111, and
the reinforcing plate 112 are referred to as a heater unit 110.
[0034] Both ends of the core 131 of the pressurizing roller 130 are
rotatably held by the frame of the apparatus (not illustrated) with
bearings. The pressurizing roller 130 is driven to be rotated by a
motor (not illustrated) at a predetermined rate in the arrow
direction in FIG. 1 while pressure is being applied to the outer
circumferential surface of the fixing belt 120.
[0035] In the heater unit 110, both ends of the reinforcing plate
112 are fixed to the frame of the apparatus (not illustrated). The
fixing belt 120 is fitted onto the heater unit 110. The heater unit
110 is pressed against the inner circumferential surface of the
fixing belt 120.
[0036] For this reason, the fixing belt 120 is rotated through the
recording material 141 conveyed following the rotation of the
pressurizing roller 130, so that the nip portion for sandwiching
the recording material 141 is formed by the pressurizing roller
130, the fixing belt 120, and the heater 200. At this time, by
electric conduction of the resistance heating element 212 of the
heater 200 which slides with the inner circumferential surface of
the fixing belt 120, the fixing belt 120 is heated in the sliding
surface (contact surface) with the heater 200, and is adjusted to
reach a predetermined temperature.
[0037] The recording material 141 sandwiched by the nip portion is
conveyed in the arrow direction illustrated in FIG. 1 by rotations
of the pressurizing roller 130 and the fixing belt 120. At this
time, an unfixed toner 142 on the recording material 141 is heated
by the heated fixing belt 120 as a heat source to be fixed onto the
recording material 141.
[0038] It should be noted that the thermal fixing apparatus of a
fixing belt-pressurizing roller type is not limited to the
embodiment illustrated in FIG. 1. In the embodiment illustrated in
FIG. 1, the heater 200 serving as a heating member is also used as
the pressurizing member. In other words, the pressurizing member is
constituted by the heating member. However, the pressurizing member
and the heating member may be provided as separate members in the
thermal fixing apparatus. In that case, the heater 200 is brought
into contact with the inner circumferential surface of the fixing
belt 120 at a position different from the position illustrated in
FIG. 1 to heat the fixing belt 120. Further, in that case, as the
pressurizing member, a laminate structured body including a base
211, an intermediate layer, and an Si-DLC film 214 in this order
may be employed.
[0039] Needless to say, besides the embodiment above, the present
disclosure can also be applied to a thermal fixing apparatus
according to Japanese Patent Application Laid-Open No. 2010-122450
which heats the fixing belt by electromagnetic induction heating.
Favorable sliding properties can be obtained by disposing the
sliding member according to the present disclosure on the surface
of the pressurizing apparatus which presses the fixing belt and
slides with the fixing belt.
[0040] FIG. 3 is a schematic cross-sectional view of an
electrophotographic full-color printer of a laser exposure type,
which is one example of an electrophotographic image forming
apparatus including a thermal fixing apparatus 100 of the fixing
belt-pressurizing roller type according to one embodiment according
to the present disclosure. A printer 300 includes toner image
forming apparatuses 311a to 311d, a primary transfer apparatus 320,
a secondary transfer apparatus 330, a thermal fixing apparatus 100,
a sheet feeder 341, a sheet feed roller 342, a sheet discharge tray
343, an external host apparatus (not illustrated), and a laser
light source for exposure (not illustrated). In response to the
input image information from an external host apparatus (not
illustrated), a full-color image can be formed onto the recording
material 141, and can be output.
[0041] Based on a color separation image signal input from an
external host apparatus (not illustrated), toner images are formed
on the surfaces of the drum-shaped electrophotographic
photoreceptors, which are incorporated in yellow, magenta, cyan,
and black toner image forming apparatuses 311a to 311d, by a laser
exposure method using a laser light source for exposure (not
illustrated). The electrophotographic image forming process by the
laser exposure method is known, and thus the description thereof
will be omitted.
[0042] The primary transfer apparatus 320 includes an endless
flexible primary transfer belt 321, a primary transfer roller 322,
and a tension roller 323.
[0043] The toner images of the four colors formed by the toner
image forming apparatuses 311a to 311d are transferred and
superimposed onto the primary transfer belt 321 by the transfer
roller, the primary transfer belt 321 being extended by the tension
roller 323 and a secondary transfer-facing roller 332 to be rotated
around them. Thus, a non-fixed full-color toner image is formed on
the primary transfer belt.
[0044] On the other hand, the recording material (paper sheet) 141
is conveyed at a predetermined sheet feeding timing by a sheet feed
roller 342 from the sheet feeder 341 to a secondary transfer
apparatus 330 including a secondary transfer roller 331 and the
secondary transfer-facing roller 332. Here, the non-fixed
full-color toner image (unfixed toner image) on the primary
transfer belt 321 is transferred onto the recording material (paper
sheet) 141.
[0045] Subsequently, the recording material (paper sheet) 141 is
conveyed to the thermal fixing apparatus 100, and is heated by the
thermal fixing apparatus 100. The non-fixed full-color toner image
on the recording material (paper sheet) 141 is melted and mixed by
heating, and is fixed onto the recording material (paper sheet) 141
as a fixed image.
[0046] Subsequently, the recording material (paper sheet) 141
having the fixed toner image is discharged to the sheet discharge
tray 343.
[0047] The Si-DLC film 214 in FIG. 2 can be formed by physical
vapor deposition such as arc deposition using silicon-containing
graphite as a raw material or sputtering, or chemical vapor
deposition using a hydrocarbon gas and silane gas as raw
materials.
[0048] More preferred is physical vapor deposition using
silicon-containing graphite as a raw material because the hydrogen
content in the DLC film is readily reduced.
[0049] As one example, an Si-DLC film forming apparatus 400 by arc
deposition is illustrated in FIG. 4. The Si-DLC film forming
apparatus 400 includes a film forming chamber 410 where a film
forming treatment is performed, an arc plasma generating chamber
420 where arc plasma discharge is generated to evaporate a film
material, and a duct filter 430 which transports the film material
generated in the arc plasma generating chamber 420 to the film
forming chamber 410.
[0050] The film forming chamber 410 is kept in vacuum by a vacuum
pump (not illustrated). A base 412 for film formation is disposed
in the film forming chamber 410 using a base holder 411. The base
holder 411 can be rotated or moved during film formation as needed
to form a film suitable for the shape of the base 412 for film
formation.
[0051] The arc plasma generating chamber 420 is kept in vacuum by a
vacuum pump (not illustrated) as the film forming chamber 410. A
silicon-containing graphite target 421 is disposed in the arc
plasma generating chamber 420. The silicon-containing graphite
target 421 is connected to an arc discharge power supply 422 for
generating arc discharge. A striker 423 for igniting arc discharge
and an anode 424 for arc discharge are disposed above the
silicon-containing graphite target 421.
[0052] The duct filter 430 includes a duct coil 431 for generating
a magnetic field for deflecting the film material. The duct coil
431 is connected to a power supply 432 for the duct coil for
electrically conducting the duct coil 431. The distal end of the
duct filter 430 includes a scan coil 433 which generates a magnetic
field for scanning charged particles of the film material. The scan
coil 433 is connected to a power supply 434 for the scan coil. The
duct filter 430 is insulated from the film forming chamber 410 and
the arc plasma generating chamber 420 with an insulation member
435. The duct filter 430 is connected to a power supply 436 for the
duct filter to enable control of the potential.
[0053] Electricity is applied from the arc discharge power supply
422 when the grounded striker 423 is brought into contact with or
is detached from the silicon-containing graphite target 421.
Thereby, arc plasma can be generated between the silicon-containing
graphite target 421 and the anode 424. The arc plasma causes the
film material to evaporate from the silicon-containing graphite
target 421.
[0054] When the arc plasma causes the silicon-containing graphite
target 421 to evaporate, fine particles of about several
micrometers called droplets are generated. Such droplets are
graphite rather than the DLC. While graphite has an advantage in
that the coefficient of friction is reduced, it also has a
disadvantage in that the film hardness is reduced. In addition,
graphite forms protrusions on the film surface, resulting in an
increase in surface roughness of the film. For this reason, the
number of droplets is adjusted as needed.
[0055] The duct filter 430 is curved, which transports the film
material generated in the arc plasma generating chamber 420 to the
film forming chamber 410. The film material evaporated by the arc
plasma, which are charged particles, are transported along the axis
of the duct filter 430 to the film forming chamber 410 by the
magnetic field formed inside the duct filter 430 by the duct coil
431 and the power supply 432 for the duct coil. In contrast, the
droplets are often neutral. For this reason, the droplets travel
straight without being deflected by the magnetic field formed
inside the duct filter 430, to collide the curved portion of the
duct filter 430. Thus, the amount of the droplets to be transported
to the film forming chamber 410 is reduced and adjusted.
[0056] The film material is generated in the arc plasma generating
chamber 420, and is transported through the duct filter 430 to the
film forming chamber 410. Thereafter, the film material collides to
the base 412 for film formation to be deposited thereon.
[0057] The amount of the film material to be transported and the
amount of the droplets are adjusted by controlling the potential by
the power supply 436 for the duct filter connected to the duct
filter 430.
[0058] The oil film present between the contact surface of the
pressurizing member and the inner circumferential surface of the
first member in the thermal fixing apparatus according to the
present disclosure contains a fluorinated oil and a silicone oil.
The oil film may further contain a thickening agent such as PTFE
particles. PTFE is particulate, and the primary average particle
size is a value measured with an electron microscope, such as 0.1
to 1.0 .mu.m.
[0059] Such an oil film is formed of a lubricant prepared by mixing
a silicone oil with a fluorinated grease containing a fluorinated
oil and a thickening agent, for example.
[0060] If the oil film contains PTFE, the amount of PTFE compounded
is preferably adjusted in the range of 10 to 100 parts by mass,
particularly 20 to 80 parts by mass based on 100 parts by mass of
the fluorinated oil.
[0061] For example, perfluoropolyether (PFPE) can be suitably used
as the fluorinated oil. PFPE is a polymer having the repeating unit
of perfluoroalkylene ether. Specific examples of perfluoroalkylene
ether include perfluoromethyl ether, perfluoroethyl ether,
perfluoropropyl ether, and perfluoroisopropyl ether.
[0062] Commercial products of PFPE can be used. Examples of the
commercial products include, but not limited to, PFPE represented
by the structural formula (1) (such as Demnum S-200 and Demnum S-65
(trade names), available from DAIKIN INDUSTRIES, LTD.), PFPE
represented by the structural formula (2) (such as Krytox GPL-107,
Krytox GPL-106, and Krytox GPL-105 (trade names), available from
The Chemours Company), PFPE represented by the structural formula
(3) (such as Fomblin M60 and Fomblin Z25 (trade names), available
from Solvay Specialty Polymers Inc.), and PFPE represented by the
structural formula (4) (such as Fomblin Y45 and Fomblin Y25 (trade
names), available from Solvay Specialty Polymers Inc.).
##STR00001## [0063] where n is a positive number in the range of
numeric values satisfying a requirement that the kinematic
viscosity at 40.degree. C. is in the range of 10 to 300
mm.sup.2/s,
[0063] ##STR00002## [0064] where n' is a positive number in the
range of numeric values satisfying a requirement that the kinematic
viscosity at 40.degree. C. is in the range of 5 to 1200
mm.sup.2/s,
[0064] ##STR00003## [0065] where n'' and m are each a positive
number in the range of numeric values satisfying a requirement that
the value m/n'' is 0.5 or more and 2 or less and the value of
(n''+m) is a numeric value satisfying a requirement that the
kinematic viscosity at 40.degree. C. is 10 to 900 mm.sup.2/s,
and
[0065] ##STR00004## [0066] where n'' and m' are each a positive
number, the value of m'/n''' is 20 or more and 1000 or less, and
the value of (n'''+m') is a numeric value satisfying a requirement
that the kinematic viscosity at 40.degree. C. is in the range of 10
to 700 mm.sup.2/s.
[0067] Since used in the thermal fixing apparatus, the silicone oil
is preferably a silicone oil having high heat resistance.
Specifically, for example, dimethylsilicone oil for high
temperature (such as "KF965" (trade name; available from Shin-Etsu
Chemical Co., Ltd.)) or methylphenylsilicone oil for high
temperature (such as "KF-54" (trade name, available from Shin-Etsu
Chemical Co., Ltd.)) can be used.
[0068] The content of the silicone oil in the lubricant forming the
oil film is preferably 1 to 10% by mass, particularly 3 to 7% by
mass based on the fluorinated grease.
[0069] According to one aspect according to the present disclosure,
a fixing apparatus having higher durability can be provided.
According to another aspect according to the present disclosure, an
electrophotographic image forming apparatus which can stably form
high-quality electrophotographic images can be provided.
EXAMPLES
[0070] Examples according to the embodiments will now be
described.
Example 1
[0071] In Example 1, the Si-DLC sliding film 214 in the thermal
fixing apparatus 100 according to one aspect according to the
present disclosure was prepared so that the number of hydrogen
atoms (H), the number of silicon atoms (Si), and the number of
carbon atoms (C) satisfied the requirement that the value of
(100.times.(H)/((H)+(C))) was 0.5 and the value of
(100.times.(Si)/((Si)+(C))) was 2.
[0072] The Si-DLC sliding film in Example 1 was formed on a base
surface at an arc discharge current of 50 A in the apparatus
illustrated in FIG. 4, using a graphite target having a density of
1.7 g/cm.sup.3 and an Si content of 2 atomic %.
[0073] FIG. 6 illustrates the spectrum of the 2p orbital of the
silicon atom Si in the DLC film, the spectrum being obtained by
X-ray photoemission spectroscopy (X-ray Photoelectron Spectroscopy
or XPS) using AlK.alpha. as the light source of a scanning X-ray
photoelectron spectroscope (trade name: Quantera SXM, available
from ULVAC-PHI, Inc.). Si--C bonds and Si--O bonds were observed on
the outermost surface (sliding surface) of the DLC film while Si--C
bonds were observed inside the film. The Si content
(100.times.(Si)/((Si)+(C))) obtained by XPS analysis was 2. The
hydrogen content (100.times.(H)/((H)+(C))) inside the film was 0.5
from ERDA analysis.
[0074] Using the Si-DLC sliding film 214 prepared above, a
pressurizing member including the Si-DLC sliding film 214 as a
surface layer was prepared, and a thermal fixing apparatus
illustrated in FIG. 1 was prepared.
[0075] A fluorinated grease and a silicone oil were used as
lubricants as shown in Table 1. The fluorinated grease is a mixture
of a perfluoropolyether (PFPE) oil and poly(tetrafluoroethylene)
(PTFE) as a thickening agent. The content of PTFE relative to PFPE
was adjusted in the range of 10 to 100 parts by mass based on 100
parts by mass of PFPE. The content of the silicone oil relative to
the fluorinated grease was adjusted in the range of 3 to 6% by
mass.
Example 2
[0076] In Example 2, the Si-DLC sliding film in Example 1 was
replaced by an Si-DLC sliding film having a value of
(100.times.(H)/((H)+(C))) of 0.5 or less and the value of
(100.times.(Si)/((Si)+(C))) of 3. Except for that, a pressurizing
member was prepared in the same manner as in Example 1, and a
thermal fixing apparatus illustrated in FIG. 1 was prepared. The
same lubricant as that in Example 1 was used.
Example 3
[0077] In Example 3, the Si-DLC sliding film in Example 1 was
replaced by an Si-DLC sliding film having a value of
(100.times.(H)/((H)+(C))) of 0.5 or less and a value of
(100.times.(Si)/((Si)+(C))) of 11. Except for that, a pressurizing
member was prepared in the same manner as in Example 1, and a
thermal fixing apparatus illustrated in FIG. 1 was prepared. The
same lubricant as that in Example 1 was used.
Example 4
[0078] In Example 4, the Si-DLC sliding film in Example 1 was
replaced by an Si-DLC film having a value of
(100.times.(H)/((H)+(C))) of 0.5 or less and a value of
(100.times.(Si)/((Si)+(C))) of 19. Except for that, a pressurizing
member was prepared in the same manner as in Example 1, and a
thermal fixing apparatus illustrated in FIG. 1 was prepared. The
same lubricant as that in Example 1 was used.
Example 5
[0079] In Example 5, the Si-DLC sliding film in Example 1 was
replaced by an Si-DLC having a value of (100.times.(H)/((H)+(C)))
of 0.5 or less and a value of (100.times.(Si)/((Si)+(C))) of 1.
Except for that, a pressurizing member was prepared in the same
manner as in Example 1, and a thermal fixing apparatus illustrated
in FIG. 1 was prepared. The same lubricant as that in Example 1 was
used.
Comparative Example 1
[0080] In Comparative Example 1, the Si-DLC sliding film in Example
1 was replaced by an Si-DLC film having a value of
(100.times.(H)/((H)+(C))) of 0.5 or less and a value of
(100.times.(Si)/((Si)+(C))) of 50. Except for that, a pressurizing
member was prepared in the same manner as in Example 1, and a
thermal fixing apparatus illustrated in FIG. 1 was prepared. The
same lubricant as that in Example 1 was used.
Comparative Example 2
[0081] In Comparative Example 2, the Si-DLC sliding film in Example
1 was replaced by a DLC film having a value of
(100.times.(H)/((H)+(C))) of 0.5 or less and a value of
(100.times.(Si)/((Si)+(C))) of 0. Except for that, a pressurizing
member was prepared in the same manner as in Example 1, and a
thermal fixing apparatus illustrated in FIG. 1 was prepared. The
same lubricant as that in Example 1 was used.
Comparative Example 3
[0082] In Comparative Example 3, the Si-DLC sliding film in Example
1 was replaced by an Si-DLC film having a value of
(100.times.(H)/((H)+(C))) of 0.5 or less and a value of
(100.times.(Si)/((Si)+(C))) of 3. The lubricant used was the
fluorinated grease used in Example 1. Except for these, a
pressurizing member was prepared in the same manner as in Example
1, and a thermal fixing apparatus illustrated in FIG. 1 was
prepared.
EVALUATION
[0083] Table 1 shows the results of evaluation of the durability
life of the thermal fixing apparatuses in Examples 1 to 5 and
Comparative Examples 1 to 3. A reduction in sliding properties
causes abnormalities such as abnormal sounds due to stick-slip
(adhesion) or breakage of the fixed film. The time until such
abnormalities occurred was evaluated.
[0084] For the test conditions, the temperature of the heater base
was 200.degree. C., and the pressure applied to the sliding surface
of the heater base was 0.2 MPa. The sheet feeding rate (the rate of
the fixed film sliding with the surface of the heater base) was 350
mm/sec, and was 82 mm/sec in examination of the abnormal sounds due
to stick-slip. The former setting is for the purpose of sliding at
a high speed to shorten the time needed for evaluation, and the
latter setting in the examination of the abnormal sounds due to
stick-slip is for the purpose of sliding at a low speed at which
stick-slip readily occurs. In Examples 1 to 4, the examination of
the abnormal sounds was performed at 200 hours from the start of
the durability test or later.
[0085] In Examples 1 to 5 and Comparative Examples 1 to 3, abnormal
sounds were generated due to stick-slip although the fixed film was
not broken. While abnormal sounds were generated within 200 hours
from the start of the test in Comparative Examples 1 to 3, abnormal
sounds were generated at 200 hours from the start of the test or
later in Examples 1 to 4. Specifically, abnormal sounds were
generated after 400 hours in Example 1, after 344 hours in Example
2, after 296 hours in Example 3, and after 265 hours in Example 4
from the start of the test. In all of Examples 1 to 4, the
durability life was increased by dozens of percentage relative to
that of Comparative Example.
TABLE-US-00001 TABLE 1 Durability time (reference time for Silicon
atom determination: in DLC film Lubricant 200 hours) Example 1 2%
Fluorinated grease OK (420 hours) and silicone oil Example 2 3%
Fluorinated grease OK (450 hours) and silicone oil Example 3 11%
Fluorinated grease OK (296 hours) and silicone oil Example 4 19%
Fluorinated grease OK (265 hours) and silicone oil Example 5 1%
Fluorinated grease OK (249 hours) and silicone oil Comparative 50%
Fluorinated grease NG Example 1 and silicone oil Comparative 0%
Fluorinated grease NG Example 2 and silicone oil Comparative 3%
Fluorinated grease NG Example 3 * Fluorinated grease: "MOLYKOTE
HP300" (trade name, available from DuPont Toray Specialty Materials
K.K.) * Silicone oil: "KF965" (trade name, available from Shin-Etsu
Chemical Co., Ltd.)
[0086] While the present disclosure has been described with
reference to exemplary embodiments, it is to be understood that the
disclosure is not limited to the disclosed exemplary embodiments.
The scope of the following claims is to be accorded the broadest
interpretation so as to encompass all such modifications and
equivalent structures and functions.
[0087] This application claims the benefit of Japanese Patent
Application No. 2020-100377, filed Jun. 9, 2020, which is hereby
incorporated by reference herein in its entirety.
* * * * *